Flexible Path? What?

On Thu, 5 Nov 2009 12:21:03 +0000 (UTC), Yama
wrote:

: Two Ares V-Lites offer *more* payload than an Ares V and an Ares I,
: and because both launchers are identical both pads can be the same,
: simplifying ground handling and launch preparations. Dumping Ares I
: for Ares V-Lite improves the situation, rather than limiting it.

It will also mean smaller and individually less capable mission modules,

It does no such thing. Orion and Altair on one Ares V-Lite, the EDS on
the other.

and less capability for direct cargo missions.

Not with orbital refueling.

Here's what Mike Griffin
has to say about Ares V Lite:

Dr. Griffin is totally, hopelessly partial to Ares I / Ares V. He
selected it, with more than a few claiming he stacked the deck against
any other alternative. He's why we're in this mess in the first place.

"The recommendation in favor of the dual-launch "Ares-5 Lite" approach as the baseline
for lunar missions is difficult to understand. It violates the CAIB recommendation
(and many similar recommendations) to separate crew and cargo in whatever post-Shuttle
human space transportation system is to be developed.

Which was a very bad, very knee-jerk recommendation, poorly justified.
If your Orion has a Launch Escape System, what difference does it make
if cargo is riding on the rocket below the Orion (a'la Apollo Saturn
V)? Orion can eject from a failing Ares V-Lite as easily as it could a
failing Ares I.

Further, the dual-Ares-5 Lite mission architecture
substantially increases the minimum cost for a single lunar mission as compared to the
Ares-1/Ares-5 approach, a recommendation which is difficult to understand in an already difficult
budgetary environment.

Not so difficult to understand in light of development costs. Ares I +
Ares V require roughly twice the development costs of Ares V-Lite
(which can use existing SSME, existing ET tooling and existing SRBs).
And they require more production facilities (Ares I Upper Stage isn't
needed in Ares V-Lite architecture) plus two brand new and dissimilar
launch pad designs.

Finally, the Ares-5 Lite is nearly as expensive to develop as the Ares-5,

Not by a long shot. No new SRB design is needed at all, for starters.
No RS-68B development is needed (use SSME, which NASA is reconsidering
anyway). No retooling Michoud for 33-ft diameter tankage is needed. No
new Crawler is needed to haul the vehicle to the pad.

but offers significantly less payload to the moon when used -- as will be required -- in a one-way,
single-launch, cargo-only mode.

Not with orbital refueling. The cargo-only launch tops off its tanks
at the depot. You actually get greater payload this way.

(The LEO payload difference of 140 mt for Ares-5 Lite and 160 mt for
Ares-5 masks a much greater difference in their lunar payload capability.)

Hence the emphasis on the refueling architecture.

All parties agree that a
heavy-lift launcher is needed for any human space program beyond LEO. Because of the economies of
scale inherent to the design of launch vehicles,

Economies of scale would be much better served with one launch vehicle
in production, instead of two.

Not to mention, are you going to use Ares V Lite to launch crews to the
ISS?

Only for the test flights. Operationally, hand that task over to
SpaceX or another commercial provider, who are chomping at the bit for
the job. If they don't pan out, Ares V-Lite / Orion launch costs can
be somewhat mitigated by also carrying an MPLM-equivalent of cargo, or
Ares V-Lite can be launched without its upper stage (Ares V-Very Lite,
I guess!)

: Even if this were practical (which I doubt), you'd still have to come up
: with the larger craft for Mars mission, even if it's just Phobos or Mars Flyby.

: The craft, but not the lander/launcher. Getting down to the Mars
: surface and launching again are going to be the monster costs of a
: Mars mission. Flexible path does things incrementally, instead of
: paying for everything in one fell swoop, which is the case if
: President Obama announces "we're going to Mars by 2025!"

Okay, this just makes absolutely no sense. You STILL have to pay for
that lander, eventually.

I'm not really the biggest fan of the "look but don't touch" Mars
idea, either. But I can see why it is appealing to some. You don't
have to go to Congress next year and ask for $75 billion more. You
"only" have to ask for $50 billion more. Its an easier sell to
Congress and the people, because you prove each step along the way
before getting to the humongous cost and risk... the actual Mars
lander/launcher.

Sure, we'll pay for this eventually either way, but it doesn't lock us
into paying for everything until we know the infrastructure works.

Meanwhile, you are mucking around doing missions
which cost a lot, yet do little to actually advance the cause for manned Mars
mission.

Except build confidence, reestablish deep space operations, prove
long-duration life support beyond reach of resupply, demonstrate
radiation protection. Retiring a great amount of risk before taking
the final step to the surface of Mars is no small accomplishment.

There have been five service missions for HST. Adding the costs up,
when you include designing all the hardware, easily makes up cost
of JWST.

No, its very close in costs. But we got more from those five missions
(well, four of them anyway) than just keeping Hubble going. We
replaced instruments with brand new state-of-the-art successors, four
times. They also added instruments in other wavelengths than were
installed originally (NICMOS, for example) and we got more powerful
instruments in visible light and UV that JWST lacks. But JWST still
costs $4.5 billion for just a (very good) IR telescope. In many ways,
we got four new astronomy satellites for about the cost of JWST. Not
too shabby really.

: A couple of development missions (which could be used to launch
: satellites or cargo to the Space Station as their primary objective)
: eats up all the savings of full-scale development and, say ten years
: of Ares V launches? I don't think so. And we just happen to have a
: Space Station up there just waiting to take on an experiment like
: that.

This is pretty goofy logic. Apparently, cost of developing
a 5.5 segment booster from 5-segment booster

....and RS-68B, and 33-ft tankage, and a new freighter to haul the
stage to KSC, and a new Crawler with a reinforced Crawlerway to handle
the weight, and sacrificing Orion reusability because Ares I can't
handle the weight of the original Orion, and cutting Orion from 6 to 4
crew because Ares I can't handle the original Orion...

Not that 5.5 segment is going to be cheap. Look at 5 segment's high
cost, and how everyone is crying that Ares I-X was nothing because the
four segment SRB is too different than the five segment SRB. The same
will be true of 5.5 segment SRB. A couple of dedicated Centaur flights
would undoubtedly be cheaper than 5.5 segment SRB development.

is too high, but
developing whole new technology, with several dedicated test missions,

Technology with a potential huge payoff for a great number of
customers, versus just NASA's manned program. We could very possibly
get a commercial partnership (ULA) to cost-share this technology. And
again, not necessarily dedicated test missions: Two Space Station
resupply missions could sacrifice a little payload to the prop
transfer demo hardware. These missions already have rendezvous and
docking capability.

I see it as something like LCROSS's use of a Centaur that was going to
the moon anyway.

not to mention the costs of actually launching refuel missions when and
if the technology actually becomes available, is not.

Contract out the refueling missions to the lowest bidder. SpaceX would
love the job. There are other low-cost launcher ideas out there that
just need a market case to get the necessary capital investment. Fuel
to LEO would be a substantial market. It might even justify a true
RLV, which would help everybody.

Brian

"Brian Thorn" wrote in message
...

Which was a very bad, very knee-jerk recommendation, poorly justified.
If your Orion has a Launch Escape System, what difference does it make
if cargo is riding on the rocket below the Orion (a'la Apollo Saturn
V)? Orion can eject from a failing Ares V-Lite as easily as it could a
failing Ares I.

If anything a bit easier since the capsule won't be quite on top of the SRBs
and the vibration problem should be mitigated a bit more.


All parties agree that a
heavy-lift launcher is needed for any human space program beyond LEO.
Because of the economies of
scale inherent to the design of launch vehicles,

Economies of scale would be much better served with one launch vehicle
in production, instead of two.

Agreed. And economies of scale don't appear to be quite as important as
complexity.

Brian



--
Greg Moore
Ask me about lily, an RPI based CMC.

Brian Thorn wrote:
: On Thu, 5 Nov 2009 12:21:03 +0000 (UTC), Yama
: wrote:
: : Two Ares V-Lites offer *more* payload than an Ares V and an Ares I,
: : and because both launchers are identical both pads can be the same,
: : simplifying ground handling and launch preparations. Dumping Ares I
: : for Ares V-Lite improves the situation, rather than limiting it.
:
: It will also mean smaller and individually less capable mission modules,

: It does no such thing. Orion and Altair on one Ares V-Lite, the EDS on
: the other.

Except that Ares V Lite can't do that. It can't launch both Orion and Altair on
one launch.

: and less capability for direct cargo missions.

: Not with orbital refueling.

....and there go the cost savings.

: "The recommendation in favor of the dual-launch "Ares-5 Lite" approach as the baseline
: for lunar missions is difficult to understand. It violates the CAIB recommendation
: (and many similar recommendations) to separate crew and cargo in whatever post-Shuttle
: human space transportation system is to be developed.

: Which was a very bad, very knee-jerk recommendation, poorly justified.

I disagree. Manned-only launch keeps things simple. Simple is good.

: Finally, the Ares-5 Lite is nearly as expensive to develop as the Ares-5,

: Not by a long shot. No new SRB design is needed at all, for starters.

Except that 5-segment booster isn't quite ready yet and needs plenty of development,
which are part of the Ares I development costs. I'm again not getting the logic of
cancelling Ares I to save on development cost of 5-segment booster, which has to be
developed anyway for Ares V Lite.

: No RS-68B development is needed (use SSME, which NASA is reconsidering
: anyway).

Actually they planned to use RS-68A for Ares V Lite. SSME is complicated and
expensive.

: Not to mention, are you going to use Ares V Lite to launch crews to the
: ISS?

: Only for the test flights.

I was kidding of course - by the time Ares V lite comes around, ISS will be on its
last legs or deorbited. That is one of the problems of Ares V lite concept - spaceflight
gap will be doubled or tripled.

Operationally, hand that task over to
: SpaceX or another commercial provider, who are chomping at the bit for
: the job.

So you would develope second launcher after all?

I'm getting really puzzled where from these supposed cost savings are meant to come.
Outsourcing the job might reduce the costs somewhat, but not by order of magnitude.

: Meanwhile, you are mucking around doing missions
: which cost a lot, yet do little to actually advance the cause for manned Mars
: mission.

: Except build confidence, reestablish deep space operations, prove
: long-duration life support beyond reach of resupply, demonstrate
: radiation protection. Retiring a great amount of risk before taking
: the final step to the surface of Mars is no small accomplishment.

Much of that could be easily achieved by unmanned test mission done while
actual mission is being prepared.

: : A couple of development missions (which could be used to launch
: : satellites or cargo to the Space Station as their primary objective)
: : eats up all the savings of full-scale development and, say ten years
: : of Ares V launches? I don't think so. And we just happen to have a
: : Space Station up there just waiting to take on an experiment like
: : that.
:
: This is pretty goofy logic. Apparently, cost of developing
: a 5.5 segment booster from 5-segment booster

: ...and RS-68B, and 33-ft tankage, and a new freighter to haul the
: stage to KSC, and a new Crawler with a reinforced Crawlerway to handle
: the weight, and sacrificing Orion reusability because Ares I can't
: handle the weight of the original Orion, and cutting Orion from 6 to 4
: crew because Ares I can't handle the original Orion...

: Not that 5.5 segment is going to be cheap. Look at 5 segment's high
: cost, and how everyone is crying that Ares I-X was nothing because the
: four segment SRB is too different than the five segment SRB. The same
: will be true of 5.5 segment SRB. A couple of dedicated Centaur flights
: would undoubtedly be cheaper than 5.5 segment SRB development.

Yes, all of that is indeed going to be much cheaper than developing whole new
modules with whole new technology, and much less risky. Constellation is not
going to be threatened by technical risk of developing new freighter for Ares V
lower stage. It can be if the untried refuelling technology fails or is delayed.
Both the ship and the crawler have to be refurbished or replaced at some point
in any case.

: is too high, but
: developing whole new technology, with several dedicated test missions,

: Technology with a potential huge payoff for a great number of
: customers, versus just NASA's manned program. We could very possibly
: get a commercial partnership (ULA) to cost-share this technology. And
: again, not necessarily dedicated test missions: Two Space Station
: resupply missions could sacrifice a little payload to the prop
: transfer demo hardware. These missions already have rendezvous and
: docking capability.

....and if the technology fails, or is severely delayed, your entire architecture
is blown.

What service missions are you talking about, btw? Progress, or ATV? Dragon will not
have orbital rendezvous and automatic docking capability.

: Contract out the refueling missions to the lowest bidder. SpaceX would
: love the job. There are other low-cost launcher ideas out there that
: just need a market case to get the necessary capital investment. Fuel
: to LEO would be a substantial market. It might even justify a true
: RLV, which would help everybody.

Awfully lot of "could, may, might" there. That doesn't cut it. Any alternative
for Ares I/V architecture would be interesting only if it cuts both technical risks
and costs. Orbital refuelling schemes are very dubious in the latter and definite
no in the former. Hence, I see no reason adopting them.